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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/guid.h"
#include <stdint.h>
#include "base/rand_util.h"
#include "base/strings/stringprintf.h"
namespace base {
std::string GenerateGUID() {
uint64_t sixteen_bytes[2] = {base::RandUint64(), base::RandUint64()};
// Set the GUID to version 4 as described in RFC 4122, section 4.4.
// The format of GUID version 4 must be xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx,
// where y is one of [8, 9, A, B].
// Clear the version bits and set the version to 4:
sixteen_bytes[0] &= 0xffffffffffff0fffULL;
sixteen_bytes[0] |= 0x0000000000004000ULL;
// Set the two most significant bits (bits 6 and 7) of the
// clock_seq_hi_and_reserved to zero and one, respectively:
sixteen_bytes[1] &= 0x3fffffffffffffffULL;
sixteen_bytes[1] |= 0x8000000000000000ULL;
return RandomDataToGUIDString(sixteen_bytes);
}
// TODO(cmasone): Once we're comfortable this works, migrate Windows code to
// use this as well.
std::string RandomDataToGUIDString(const uint64_t bytes[2]) {
return StringPrintf("%08X-%04X-%04X-%04X-%012llX",
static_cast<unsigned int>(bytes[0] >> 32),
static_cast<unsigned int>((bytes[0] >> 16) & 0x0000ffff),
static_cast<unsigned int>(bytes[0] & 0x0000ffff),
static_cast<unsigned int>(bytes[1] >> 48),
bytes[1] & 0x0000ffffffffffffULL);
}
} // namespace base
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